Delta tells you how fast an option moves today. Gamma tells you how fast that speed changes as the stock moves. In one sentence: gamma is the acceleration of your delta. When gamma is high, the position you hold today is not the position you will hold tomorrow if the stock moves.

Gamma in One Line

If your option has delta 0.30 and gamma 0.05, a $1 move up means tomorrow your delta is roughly 0.35. Another $1 up and delta is ~0.40. Your share-equivalent exposure is quietly climbing while you sleep.

Low γ
Deep ITM or far OTM
Gamma is small. Delta barely changes with moves. Position size stays roughly constant — what you see is what you own.
High γ
At-the-money · near expiry
Gamma peaks where delta is near 0.50 and time is running out. A $2 stock move can flip delta from 0.40 to 0.70 — you are suddenly much longer than you signed up for.
Short γ
Short options = negative gamma
Sellers of options are short gamma. Every move against you makes your losses accelerate, not just continue. This is the hidden tail risk of "selling premium."

Why Gamma Matters More Than Delta Near Expiry

In the last 2 weeks of an option's life, gamma spikes sharply on at-the-money contracts. A cash-secured put sitting quietly at 0.30 delta can balloon to 0.80 delta overnight if the stock drops toward the strike. You thought you had 30 equivalent shares; assignment risk is now 80.

This is why professional options traders close positions with 1-2 weeks left rather than holding to expiry — not because theta is bad (theta is good for sellers at that point), but because gamma risk becomes unmanageable.

Every time you check net delta on your options book, also ask: what does gamma say my delta will be if the stock moves 5%? If the answer is "dramatically different," your real position size is much more uncertain than the delta number suggests.

Where Gamma Shows Up in the Risk Report

Open the Risk Report from the Positions page (modal). Gamma is not displayed as a numeric cell, but its regime is flagged in two specific places:

  • DTE ≤ 30 warning per strategy group — labelled "Near expiry — elevated Gamma risk." This is the report telling you the position has crossed into the gamma-spike zone where delta moves accelerate sharply.
  • Greeks-not-provided fallback — if your data feed lacks gamma, the report estimates Greeks via the Black-Scholes-Merton model and shows a hint to enable Delta / Gamma / Theta / Vega in your Flex Query.

Raw gamma value per leg lives in the position record (API / export). A dedicated UI column is not on the report today — the DTE warning is the practical tell.

Gamma = the acceleration of your delta
High near the strike · highest near expiry · negative if you sold
Risk Report DTE ≤ 30 "elevated Gamma risk" flag is the live regime tell

Open the Risk Report →